This disclosure generally relates to ram air turbine assemblies. More particularly, this disclosure relates to a method and device for reducing structural resonances of a ram air turbine assembly.
A ram air turbine is utilized in aircraft as a backup power generator. Upon failure of the primary power generator, the ram air turbine is deployed. Deployment entails movement from a position within the aircraft to an extended position where the turbine blades are exposed to ram air outside of the aircraft. The turbine blades rotate a generator to provide electrical power, a pump to provide hydraulic power or both at the same time to aircraft systems in the absence of primary electrical and hydraulic power.
The ram air turbine is a back-up device and therefore is rarely used. However, although rarely used, it is important that the ram air turbine operate efficiently and properly when deployed. Conventional ram air turbines can encounter self-induced vibrations caused by imbalance of the turbine. The turbine imbalance is primarily caused by motion of the governor components and governor springs. The self-induced vibrations are amplified when there is a structural resonance within the operating speed range of the turbine. The vibration can degrade performance and therefore it is desirable to modify the structural resonance frequency so the ram air turbine is less susceptible to vibration.